Workflow validation failed when using conditional sequence

Problem

When using a conditional sequence or while sequence and using a decimal value as a condition, the workflow cannot be started and a message similar to this is logged in Event Viewer

Error: Microsoft.Workflow.Client.ActivityValidationException: Workflow XAML failed validation due to the following errors:

Invalid type(s) 'System.Int64'.

Solution

Upgrade Workflow Manager to at least CU 2, since the RTM version of Workflow Manager does not support the Int64 data type.

Troubleshooting guidelines